This invention relates to an exercising device and more particularly to a device which has utility in exercising a great many of the muscles and muscle groups of the human upper extremity and in particular the shoulder area thereof.
In the biomechanics of human shoulder function, there are four joints which contribute to the shoulders functional motion. They are the scapulo-thoracic, gleno-humeral, acromio-clavicular, and the sterno-clavicular. Each time the shoulder moves motion takes place in more than one of these joints. Of these the gleno-humeral and the scapulo-thoracic are responsible for the greatest amount of motion at the shoulder.
Together these joints are responsible for approximately the following amounts of motion: 180 degrees of flexion in the sagittal plane, 60 degrees of extension in the sagittal plane, 180 degrees of abduction and adduction in the frontal plane, 90 degrees of external rotation in the sagittal plane, and 90 degrees of internal rotation in the sagittal plane.
Movements of the arm at the shoulder are free, and include flexion, extension, abduction, adduction, circumduction, internal rotation, and external rotation. These movements are usually defined in relation to the body as a whole. Flexion of the shoulder is a forward movement of the arm. Extension, the reverse of this, is backward movement of the arm. Abduction is the movement of raising the arm laterally away from the body; adduction, the opposite of this, is then bringing the arm toward the side. Circumduction is a combination of all four of the above defined movements, so that the hand describes a circle. Internal rotation is a rotation of the arm about its long axis, so that the usual anterior surface is turned inward toward the body; external rotation is the opposite of this.
All movements of the arm at the shoulder can be described by the terms used above, although usually movements of the arm are combinations of two or more of the above defined movements with a multiaxial axis and plane of motion. Thus, for example, in bringing the arm across the chest in throwing an object we both flex and adduct the shoulder and usually also internally rotate it at the same time. In scratching the lower part of one's back, one extends, internally rotates, and abducts or adducts.
Over twenty major muscles cross at least one and in many cases more than one of the joints listed above on each shoulder. Their function is to create motion, and thus the ability to do work with the upper extremity. To perform a given task with precision, power, strength, endurance, and coordination, all of these muscles must be well conditioned.
Some of the shoulder muscles included are the supraspinatus, infraspinatus, teres minor, deltoid, anterior deltoid, posterior deltoid, biceps, long head of biceps, short head of biceps, upper and lower pectoralis major, subscapularis, teres major, coracobrachialis, latissimus dorsi, triceps long head. Some of the scapular muscles included are the serratus anterior, upper and lower trapezius, major and minor rhomboids, levator scapulae, and pectoralis minor.
The function of each of these muscles depends on its relative position to the joint axis it crosses, the motion being attempted, and any external stresses acting to affect motion. It is well accepted that muscles rarely act singly, rather, groups of muscles interact in many ways so that a desired movement can be accomplished. The interaction of muscles may take many different forms so that a muscle serves in a number of different capacities, depending on movement. At different times a muscle may function as a prime mover, antagonist, or a fixator or synergistically as a helper, a neutralizer or a stabilizer. Most of these muscles are continually active with any type of freely rotational shoulder movement as their role continually changes.
Biochemically the shoulder functions almost always along with the elbow. In activities of daily living and in recreational sports upper extremity movement requires synergy between these two areas. The shoulder and elbow move together although independent of one another in performing all complex activities. In order to optimally train and exercise the shoulder one must also train and exercise the elbow at the same time. In this way, the upper extremity is treated as a functional unit. All joint motions and muscle functions would be coordinated together.
There are three major joints which contribute to elbow function. They are the ulnar-humeral, radio-humeral, and the radio-ulnar. The ulnar-humeral is responsible for 135 degrees of flexion and extension while the radio-humeral and the radio-ulnar joints are responsible for 90 degrees of supination and 90 degrees of pronation. Flexion is movement in the anterior direction from the position of straight elbow, zero degrees to a fully bent position. Extension is movement in a posterior direction from the fully bent position to the position of a straight elbow. Supination and pronation are rotational movements of the forearm. Supination is with the palm up and thumb rotated laterally. Pronation is with the palm down and thumb rotated medially.
Over twelve major muscles effect motion at each elbow. These are the biceps, brachialis, brachioradialis, supinator, extensor capri radialis longus, pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, triceps, anconeus, supinator, pronator quadratus. Of these, the biceps anteriorly, an elbow supinator and flexor, and the triceps posteriorly, an elbow extensor also cross the shoulder. Like the shoulder muscles, these elbow muscles are continually active as there role changes in performing the complex activities of daily living, work, and recreational sports.
An in depth review of the biomechanics of the shoulder and elbow show a variety and considerable number of muscles and articulations whose combined function result in great strength and precision of movement anywhere in the range of motion. Each component muscle and joint has a unique function depending on the motion being attempted. In order to fully train and strengthen upper extremity musculature, one must use this biomechanical knowledge and work in all planes, patterns, and extremes of motion exercising the body part as it will function. Only in this way can total neuromuscular balance, coordination, and proprioception be achieved.
Known types of upper extremity exercise and/or exercise devices include isometric, isotonic, isokinetic, and special cases.
Isometrics is an exercise done without any joint motion taking place. The hand would be pressed against an immovable object such as a wall. Strength can be improved but only in the range of motion in which it is being exercised. Since only one position and one angle can be used at one time, this becomes a time consuming approach if one tried to exercise throughout all points in the range of motion of the shoulder and elbow. This also cannot be considered a functional exercise since the upper extremity rarely moves against an immovable object.
Isotonic exercises are done against a movable resisting force. The resisting force is usually free weights. This is probably the most common method of exercise for the upper extremity as it is relatively inexpensive and readily available in gyms. A weight is held in the hand and moved in opposition to gravity. It is a functional advantage to be able to move through a full range, but because of this gravitational effect on the weight, body position must be continually changed for all muscles to be exercised. In the backlying or supine position, a weight held in the hand and pushed straight up vertically (bench press position) exercises the anterior chest and posterior upper arm muscles. In order to exercise the posterior shoulder and the anterior arm muscles, one would have to switch to a facelying or prone position and pull the hand held weight upward again against gravity. The time commitment here becomes a disadvantage as does ones having to make changes in the amount of free weight used in order to afford a smooth progressive overload. In this form of exercise, the load remains constant and the amount of stress on the muscle will vary. The most difficult point in the range is the initial few degrees with a movement to overcome inertia. The other disadvantage occurring here is one of leverage. As the upper extremity comes closer to the vertical position. leverage with respect to the joint increases and work becomes easier. This also creates a variability in the degree of muscle tension throughout the range of motion. Isotonic exercises can be performed on Nautilus, Universal Gym and other similar machines which achieve a more uniform resistance. Again body position must be changed to affect different muscles. This is achieved by moving on to a different apparatus. A major disadvantage is that motion on these machines is confined to a straight plane movement without deviation which is not how the biomechanical components of the upper extremity are used.
Isokinetic exercise involves a constant speed and a variable resistance. There are many hydraulic (Orthotron by Cybex), electromechanical (Cybex by Cybex division of Lumex), and pneumatic (Kessler) isokinetic units on the market. These are all limited to one straight plane at a time as with Universal and Nautilus. The advantage with these isokinetic devices is that resistance is in either direction of the single place of movement, i.e., flexion and extension of the shoulder, without changing body position. The isotonic Universal and Nautilus afford resistance only in one direction against gravity before changing body position. On exercise machines by Cybex, Hydragym, Kessler, etc. (isoKinetic straight plane machines) either the axis of motion, one's body position, or the apparatus itself must be changed to affect a variety of musculature in the shoulder and elbow. These machines are not functional to the biomechanics of the upper extremity since motion cannot take place through different planes simultaneously. A recently developed shoulder hydraulic isokinetic exerciser by Isotechnologies does allow simultaneous motion through planes of shoulder motion but, as with other isokinetic machines, will not allow any functional independent elbow exercise to occur simultaneously along with shoulder motion. Therefore this is not a biomechanically sound approach for the upper extremity.
Included in special cases are the wall pulley, frictional and elastic resistance exercise devices for the shoulder. They will be considered together because their axis of motion is stationary, their resistance direction is uniaxial and the effective line of pull straight plane. These are similar to isotonic unidirectional resistance methods with the exception that here the axis of motion or height of the wall pulley or hook for fastening an elastic band may be changed in order to affect different muscle, while the line of pull of gravity cannot be changed therefore one's body positioning must be changed with isotonic-free weights.
Like with hand held free weights, the major advantage is the upper extremities full range of motion through exercise. The drawback for this functional range of shoulder and elbow motion is unidirectional resistance, fixed axis, and only one resistance for both the shoulder and elbow. The elbow being a smaller joint with less cross sectional muscle will require less resistance than the shoulder. When using one resistance for both joints of the upper extremity, the weaker of the two joints would limit and determine the resistance setting for the whole extremity.
Despite the availability of the above devices and exercise types, there remains a need for a device which both accomplishes the advantages of known devices but yet eliminates their drawbacks. Such objects are accomplished by the present invention in the form of a device which is compact, simple to utilize and of relative low cost. Such device is referred to as the Multiaxial Upper Extremity Exerciser (MUEE). Mechanically the Multiaxial Upper Extremity Exerciser (MUEE) functions as a three joint frictional resistance exerciser. Friction provides for smooth gliding movements in all joints at all resistance settings. Resistance is adjustable from very little to extremely high loads. All resistance is calibrated and measured in a convenient scale such as pounds or footpounds. This calibration allows for recording of progress and for ones working with uniform resistances from day to day. Once resistance as been set, it may remain constant or become variable depending on the speed of motion.
The present device includes upper and lower resistance systems which cooperate with each other to achieve the overall results and flexibility of the device. The lower resistance system may include two multiaxial friction joints. These joints allow for a full range of motion in the gleno-humeral, scapulothoracic, acromio-clavicular, and costo-clavicular joints. The upper frictional resistance joint which glides and rotates along the shaft attached to the top joint of the lower frictional resistance system allows for full elbow flexion, extension, pronation, and supination. Both the upper and lower resistance systems have independent resistance settings. This allows for less resistance to be used at the elbow than at the shoulder which is more demanding. Resistance can be fine tuned depending on the specific requirements of the extremities' component parts at that point in time.
The design and placement of this three-axis, mechanical system allows the shoulder and elbow to move through a full range of motion between all planes independently and simultaneously with synergy as one functional unit, as it acts biomechanically. Any straight plane, diagonal, or multiaxial movement at the shoulder can be accompanied by any related elbow motion.
Upper extremity work can be done in all planes, patterns, and extremes of motion at the same time on this device. Over twenty shoulder and twelve elbow muscles can be coordinated together. This is a functional exercise device causing group activity in the upper extremity musculature as it trains the motor units to act in all the ways it can be used in activities of daily living, work, or in recreational sports. This complete upper extremity exercise system provides comprehensive improvement in neuromuscular balance, strength, power, endurance, and coordination through a full range of motion. This will decrease the chance of injury or reinjury to the upper extremity.
With the MUEE, the total upper extremity musculature can be effectively conditioned without having to make changes in body position or exercise axis. This allows exercise regimes to be completed quickly as does the fact that resistance is multidirectional and follows any joint movement. Once the resistance is set, it will work in all directions without needing to be reset for the return motion. Exercise regimes may be designed therapeutically for the post traumatic, atrophied, stiff, and painful extremity or for high levels of complete sports conditioning.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.